Galvanoplastic method and apparatus.



M. M. MERRITT.

GALVANOPLAS'HC METHOD AND APPARATUS.

APPLICATION FILED MAR. 29. I917.

Patented Oct. 22, 1918.

days.

Ewen/Ear.- mifiwew M. Merzefi.

HE sex a i MATTHEW M. MEBRITT, OF DANVERS, MASSACHUSETTS, ASSIGNOR- TOCOPPER PROD- UCTS COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OFMAINE.

To all whom it may concern:

Be it known that I, MATTHEW M. MER-- RITT, a citizen of the UnitedStates, and a resident of Danvers, co unty of Essex, Com- .posited.

the deposited metal.

sirable that the deposit of metal be as unimonwealth of Massachusetts,(whose postofiice address is Danvers, Massachusetts,) have invented anImprovement in Galvanoplastic Methods and Apparatus, of which thefollowing descriptlon, in connection with the accompanying drawings, isa specification, like characters on the drawings representing likeparts.

This invention pertains to improvements in .galvanoplastic methods andapparatus,

and more particularly, though not exclusively, to improvements inmethods and apparatus for manufacturing copper tubing and sheets bygalvanoplastic deposit.

Among the objects of the invention are to provide more perfectgalvanoplastic deposits, and to accelerate and otherwise cheapen themanufacture of such deposits.

In the drawings:

Figure 1 is a section .through a tank containing an electrolytic bath,an anode and a cathode, the latter being a mandrel adapted for use inmanufacturing copper tubes.

' Fig. 2 is a' cross section on an enlargedscale, of the mandrel withthe galvanoplastic deposit thereon.

Fig. 3 is a perspective of a larger mandrel on which a sheet of copperhas been de Fig. 4 is a perspective showing the sheet 3f popperpartially stripped from the man- It is essential to the manufactureofarticles by galvanoplastic processes that the mandrel or mold bereadily separable from It is also highly deform in thickness aspossible, that the process be accelerated and that the mold or mandrelbe preserved from deleterious chemical action and be of permanentcharacter'so that it can be used many times and' this without repeatedand expensive treatment.

Copper tubes have heretofore been'electrolytically .deposited on fusiblemandrels or on metallic mandrels from which they have been separated byburnishing orirolling to enlarge the tube. In some instances metallicmandrels for this purpose have been coated with tin or zinc, eitherelec- Specification of Letters Patent.

Patented Oct. 22, 11918.

Application filed March 29, 1917. Serial No. 158,428.

trolytically or by dipping, prior to the galvanoplastic deposit. In suchcases the separation of the deposit from the mandrel is more difiicultthan by my process hereinafter described, and usually necessitates therecoating of the mandrel after use thereof.

,Also the deposit is considerably thicker at and near the electricconnection to the mandrel and at the portion of the mandrel nearest theanode. In some instances several electric connections have beenprovided, but this merely results in increasing the numberof'irregularities in the deposit.

I have found thatby using a permanent metallic mandrel which has beencovered with .a mercury deposit by amalgamation or otherwise, I can veryreadily remove the galvanoplastic deposit'with little if any expansionof the deposit by burnishing or otherwise. I I have also found that theelectro deposit is very even on all parts of the mandrel because of thesuperior conductivity of the surface of the mandrel when coated withmercury. The mandrel. should be very smooth but the mercury coatingfills the pores or other roughnesses of the core of the mandrel, and inone sense lubricates the I The core of the mandrel may be of brass,

steel, or other metal, but I prefer the former.

1 Where the latter is used the mercury protects the steel. from thechemicals in the bath. The mercury coating is durable and -a mandrel maybe used many times without the application of a fresh-coating of mer-'cury, especially where, as when a brass mandrel is coated, there is aconsiderable chemical union of the surface of the brass and the mercury.

In the manufacture of sheets the same ad-- convenient to remove thedeposit from the mandrel by splitting the deposit lengthwise of themandrel.

While I have described andv illustrated cylindrical mandrels, it will beunderstood that the mandrels may be of any form without departing fromthe broader aspects of -my invention. It will also befunderstood that,within the scope of the appended claims, considerable changes may bemade in materials and methods, of utilizing the same. My invention andWhat I desire by Letters Patent to secure, is best defined by thefollowing claims.

Claims: v 1. The method of preparing a metallic mandrel forgalvanoplasticdeposit, which comprises coating said mandrel with mercuryamalgam.

2. The method of preparing a permanent mandrel for cury amalgam enteringinto chemical union with the surface of the mandrel.

3. The method of manufacturing articles by galvanoplastic deposit whichcomprises electrolytically depositing metalon a permanent metallicmandrel coated with a conductor fluid at ordinary temperatures andproviding per s e no substantial resistance I galvanoplastic depositwhich 1 comprises coating said mandrel with a mername to thisspecification.

to removal of said deposit from said mandrel.

4. The method of manufacturing copper tubes which comprisesgalvanoplastically depositing copper on the mercury coated surface of acylindrical mandrel, slightly en- I larging said tube by bulfing, andwithdrawing said tube from said mandrel.

5. The method of manufacturing copper sheets which comprisesgalianoplastically depositing copper on a mercury coated surface of amatrix, and subsequently stripping body portion having its surfaceamalgamated with mercury.

In testimony whereof I have signed my MATTHEW M. MERRITT.

